The invention relates to coverless V-belts having non-molded, or "raw edge" V-sides and a process for their manufacture, but more particularly, the invention relates to a V-belt having non-molded frictional driving surfaces and a process which provides for removing uncured elastomeric material from near the belt V-sides for reprocessing.
V-belts usually fall into two general categories. A covered V-belt is typically manufactured by fabricating a belt sleeve with a tensile member interpositioned between two elastomeric layers, forming V-sides in the belt by skiving away circumferential portions of one of the layers for reprocessing, annularly cutting the sleeve to form a plurality of V-belt bodies, surrounding the belt bodies with a fabric cover strip which may be impregnated with an elastomer, and curing and molding the belts in individual ring molds. Belts in this category are usually quiet running because of the fabric cover. The manufacturing process is economically desirable because the uncured skivings are reprocessable without deleterious affect on the elastomers effectiveness when finally cured.
Belts of the second category are started in a similar manner by fabricating a belt sleeve of principally two elastomeric layers that sandwich a tensile member. However, the entire sleeve is cured and annular bands are severed therefrom to form what is known as coverless or "raw edge" belts. When center cord line belts such as disclosed in U.S. Pat. No. 3,869,933 are manufactured, there is no cured skiving scrap removed between adjacent belts of a sleeve. However, the center cord line belts may not have the power transmitting capability of a "high" cord line belt where the tensile member is placed in the upper portion of the V-belt body.
When high cord line, raw edge belts are manufactured, the material removed between adjacent belts of a sleeve is not directly reprocessable because it has been cured. This is an economic disadvantage to the production of raw edge belts.
Material between adjacent belts of a belt sleeve may be removed by cutting as represented in the above patent, or the material may be removed by grinding as disclosed in U.S. Pat. No. 3,822,516 or U.S. Pat. No. 3,948,113. The raw edge belt shows some appearance advantages over a covered (banded) belt in prolonged use for some drive applications. In a raw edge belt, fibers or several plies of fabric are embedded in the elastomer layers so that portions can be exposed at the V-sides for quiet running. The material should be removed in a manner to expose the fibrous material such as by cutting or grinding. A belt having molded V-sides and no cover is unsatisfactory because a high coefficient of friction at the molded V-sides causes the belt to be aggressive by climbing out of a sheave or to be noisy. Also, the raw edge belt has a disadvantage in that it cannot be molded to some shapes such as the arching shapes of covered belts like disclosed in U.S. Pat. No. 1,988,292.
This invention is directed toward raw edge belts and a manufacturing process which substantially reduces the amount of cured elastomer that must be removed when making high cord line belts.